The international media last week gleefully reported the decision by North Korea to switch to "Pyongyang time," a half hour behind that of Seoul and Tokyo, as another example of the bizarreness of the Kim Jung-un regime. But the move was not as crazy as some may think.

What are called non-standard, factional or unique time zones, like that adopted by North Korea, deviate between 15 and 45 minutes from Coordinate Universal Time (UTC), what used to be known as Greenwich Mean Time.

Non-standard time zones already occupy great swathes of South Asia, for example, including Iran, Afghanistan, India, Nepal, Sri Lanka and Myanmar. Other nations or provinces that have adopted such time zones include Venezuela, Newfoundland in Canada, the Northern Territories and South Australia along with city of Broken Hill in Australia, and the Chatham Islands and Marquesas Islands in the Pacific.

Moreover, South Korea had a non-standard time zone, a half-hour behind that of Tokyo and conforming to North Korea's new one, between 1954 and 1961. Previously the Joseon Kingdom had the same non-standard time zone between 1908 and 1912 before the country's Japanese colonial rulers switched to what is now known as Korean Standard Time (KST).

What grabbed the international media's attention, however, was North Korea's usual over-the-top explanation for the time zone switch to UTC+8.5, which will take place on Saturday to celebrate the 70th anniversary of the liberation of the Korean peninsula from Japan.

"The wicked Japanese imperialists committed even such unpardonable crimes as depriving Korea of even its standard time while mercilessly trampling down its land with 5,000 year-long history and culture," North Korea's Presidium of the Supreme People's Assembly, the country's parliament, said in issuing the decree.

But North Korea's state-run media also included a practical reason for the measure. It noted that KST, which is used by South Korea, is based on the longitude of 135 degrees east and is appropriate for Japan, but not Korea. The new Pyongyang time is based on the longitude of 127.5 degrees east, which passes directly through the Korean Peninsula.

One reason why nations adopt non-standard time zones is that they want a time measurement that comes closest to having the sun at the highest point in the sky when the clock strikes noon, which reflects one aspect of North Korea's reasoning. This reflects the belief by some that natural biological rhythms based on darkness and light should take precedence over artificial time zones.

But as the North Korean statement also showed, politics often plays a role in what time zone is adopted. In a move similar to North Korea's, Venezuela switched to a non-standard zone in 2007 under the late president Hugo Chavez.

Chavez justified the move to put the clocks back by half an hour by saying that it would spread sunlight more evenly in Venezuela during the daylight hours and that the country was only returning to the same time zone it used between 1912 and 1964.

Analysts said that Chavez also used the time zone change to assert his authority and independence when he was facing criticism from the U.S.

Power politics have governed the choice of other time zones. Both China and India are spread over multiple time zones in theory due to their large landmasses, but they use a single time zone based on Beijing and New Delhi time respectively to promote national unity and centralized power. In addition, India decided to adopt a non-standard time zone because New Dehli was located midway between two standard time zone boundaries.

Indeed, our current global standardized time system based on GMT and 24 equal time zones was pushed by the corporate power of the railroad industry in the late 19th century to replace a fragmented time structure, known as local mean time, which was based on local calculations of the position of the sun at midday. Railroads wanted standardized zones to synchronize their timetables.

Given the current anti-Japanese sentiment in South Korea and the country's historical record of time zones, will Seoul be tempted to follow in Pyongyang's steps? Probably not, although North Korea has used the time zone change to once again try to make Seoul look like a Japanese stooge in its propaganda war.

Still, the Unification Ministry sounded defensive when asked about its response to the Pyongyang time change. It said that South Korea "is not following Japan time." Instead, it explained that KST is based on practical considerations because it brings more daylight hours to the eastern coast if it adheres to Tokyo time. But some analysts believe that Seoul has a more powerful reason to stick to KST because it ensures better defense coordination with U.S. forces based in Japan as it removes a potential source of confusion if the time zones were different.

John Burton, a former Korea correspondent for the Financial Times, is now a Seoul-based independent journalist and media consultant. He can be reached at john.burton@insightcomms.com.